On the Chemical Constitution of Warwickite. 355 
baryta, and the filtrate examined for alkalies without success. A 
portion of the original sulphuric solution was teste for phospho- 
ric acid by molybdate of ammonia, but gave no indication of its” 
presence. ‘ 
rom these experiments it appears that the only ingredients 
present in the mineral are titanic acid and magnesia, with some 
protoxyd of iron. There remained at my disposal only “200 
cess, and the ferruginous precipitate having been collected, was 
redissolved in hydrochloric acid, precipitated. by ammonia, dried 
and ignited. It weighed ‘022 grammes, and when analyzed 
after the plan described under H, gave ‘018 of pure peroxyd of 
iron equal to 0162 of protoxyd. ‘The difference of ‘004 grammes 
was considered as titanic acid, and was added to that originally 
sipitated, making in all 063 grammes. cei 
‘he magnesia in the first ammoniacal filtrate, and that in the 
n with bicarbonate of potash, were precipitated as ammo- 
hosphate which after ignition weighed ‘237 grammes = ‘087 
of magnesia. 
An accidental loss was sustained upon the original solution of 
_ the mineral, but I was obliged to complete the analysis upon that 
portion, for want of material ; it is believed that the numbers 
above given, represent the respective proportions of the several 
constituents, and that the deficiency in their sum is no more than 
corresponds to the loss. We have from 200 grammes, 
ae pee A eB 
Titanic acid, a 15 
Magnesia, ‘ : . 0870 = 435 
Protoxyd of iron, . F 0162. oe “81 
Loss on ignition, ; ; 0040: Se BO: 
1702 85:1 
If we take the deficiency of about fifteen per cent. to repre 
sent only the three ingredients above found, we have by calcula-  ~ 
¢ tion the following as the composition of the mineral. — 
: Titanicacid, . + 37-14 containing oxygen, 14°82 
agnesia, . ; 1:30 eter 20°55 - 
-Protoxyd of iron, - 995° ee # 211 
- Loss on ign., (water ?) BOO? Meshes _ 172 
eis cea 99:99." 
